1. Field of the Invention
The present invention relates to a catalyst-spreading device. More particularly, the present invention relates to a catalyst-spreading device that uniformly spreads catalyst on a substrate in a device for producing carbon nanotubes.
2. Description of the Related Art
A carbon nano-tube is formed in a shape of hexagon honeycomb by having a carbon atom bonded with three surrounding carbon atoms. Since a carbon nano-tube has superior electrical, thermal, and mechanical characteristics compared to conventional devices, it can be applied to various industrial fields including electric field-emission devices, electrochemistry, energy storages, ultra fine mechatronics systems, and organic or inorganic compound materials.
Methods to produce carbon nanotubes include a laser ablation method which produces carbon nanotubes by evaporating a test sample made of mixture of metal and graphite powder using a laser, an arc discharge method that generates arc discharge by applying voltages to two carbon pillars having different diameters and produces carbon nanotubes, a chemical vapor deposition (CVD) method that induces carbon nanotube growth by heat or plasma by injecting a source gas into a reactor, and a pyrolysis of hydrocarbon that produces carbon nanotubes in a gas phase by decomposing hydrocarbon by supplying a reaction tube heated with transition metal with liquid or gas hydrocarbon.
Specially, when carbon nanotubes are produced using the chemical vapor deposition that induces carbon nanotube growth using a catalyst, it is important for the catalyst to be uniformly spread on a substrate.
A catalyst is a material that can control a reaction rate, and when producing carbon nanotubes it is not trivial to spread powder catalyst on a substrate uniformly. For example, scattering powder catalyst on a substrate or manually spreading powder catalyst on a substrate does not guarantee uniform distribution and can decrease the yield of carbon nanotube production.
Therefore, in order to uniformly spread catalyst on a substrate an automated device that provides the substrate with catalyst. Also, for mass production of carbon nanotubes a catalyst-spreading device that can uniformly spread catalyst is required.